Subinertial Slope-Trapped Waves in the Northeastern Gulf of Mexico

Abstract Current velocity from moored arrays of acoustic Doppler current profilers (ADCPs) deployed on the outer shelf and slope, south of Mobile Bay in the northeastern Gulf of Mexico, shows evidence of alongslope, generally westward-propagating subinertial baroclinic Kelvin waves with periods of about 16 and 21 days, amplitudes of 5–10 cm s−1, and wavelengths of about 500 km. The observed waves were highly coherent over the slope between about 200 and 500 m and accounted for a significant amount of the current variability below 200 m. The source of the waves could be attributed to effects of the Loop Current on the west Florida slope but is more likely due to direct forcing by Loop Current–generated eddies impacting the experimental area.

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SEASONAL VARIABILITY OF LIGHT ABSORPTION COEFFICIENT OF SURFACE WATER

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.29244/jitkt.v7i2.11121 ◽

2016 ◽

Vol 7 (2) ◽

Author(s):

Bisman Nababan ◽

Denny A. Wiguna ◽

Risti E. Arhatin

Keyword(s):

Gulf Of Mexico ◽

Absorption Coefficient ◽

Loop Current ◽

Surface Absorption ◽

Average Value ◽

Run Off ◽

Significant Difference ◽

Coefficient Measurement ◽

Northeastern Gulf Of Mexico ◽

Offshore Region

Absorption coefficient measurement can be used in estimating water quality, optical characteristic of water column, and marine bio-optical models. The purposes of this research were to determine values and variability of sea surface absorption coefficient in the northeastern Gulf of Mexico (NEGOM) based on various seasons. The data were collected in spring, summer, and fall seasons in 1999-2000 with AC-9 instrument. The spatial distribution of absorption coefficient showed that relatively high values were generally found along the run off Missisippi, Mobile, Chochawati, Escambia, Apalachicola, and Suwannee rivers, as well as Tampa Bay. Meanwhile, relatively low values were found in offshore region. This pattern followed the distribution pattern of chlorophyll and CDOM. Based on the local region comparison of spectral average value of absorption coefficient, we found a significant difference (α = 95%) among regions with the highest value in the run off of the Mississippi and Mobile rivers, and the lowest value in the offshore region. Comparison of spectral average value of absorption coefficient among seasons at the three primary wavelengths (blue=440 nm, green=510 nm, and red=676 nm) also showed a significant difference (α = 95%) with the highest value during the summer 1999 (Su-99) and the lowest value during the spring of 2000 (Sp-00). Absorption coefficient values were influenced by oceanographic factors that varied in every season such as wind, surface currents, upwelling, the location and speed of the Loop Current, and the river discharge of fresh water into the NEGOM.Keywords: absorption coefficient, seasons, chlorophyll, CDOM, northeastern Gulf of Mexico

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Nonlocal impacts of the Loop Current on cross-slope near-bottom flow in the northeastern Gulf of Mexico

Geophysical Research Letters ◽

10.1002/2015gl063304 ◽

2015 ◽

Vol 42 (8) ◽

pp. 2926-2933 ◽

Cited By ~ 3

Author(s):

Thanh-Tam Nguyen ◽

Steven L. Morey ◽

Dmitry S. Dukhovskoy ◽

Eric P. Chassignet

Keyword(s):

Gulf Of Mexico ◽

Loop Current ◽

Northeastern Gulf Of Mexico

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Mean Flow in the Gulf of Mexico

Journal of Physical Oceanography ◽

10.1175/2007jpo3802.1 ◽

2008 ◽

Vol 38 (7) ◽

pp. 1501-1514 ◽

Cited By ~ 16

Author(s):

Wilton Sturges ◽

Kern E. Kenyon

Keyword(s):

Gulf Of Mexico ◽

Data Sources ◽

Loop Current ◽

Independent Data ◽

Ekman Pumping ◽

Mean Flow ◽

The West ◽

Net Flux ◽

Yucatan Channel ◽

Current Potential

Abstract Several independent data sources suggest that there is a net upper-layer mass flux O(3 Sv) (Sv ≡ 106 m3 s−1) to the west in the central Gulf of Mexico, even though the western gulf is a closed basin. A plausible explanation is that this net flux is pumped downward by the convergent wind-driven Ekman pumping, as is typical of all midlatitude anticlyclonic gyres. The downward flux can follow isopycnals to depths O(500–600 m) and deeper by eddy mixing; a mechanism for forcing deep water to the south through the Yucatan Channel is provided by the intrusion and ring-shedding cycle of the Loop Current. Potential vorticity maps show that a deep flow from the western gulf back to the Yucatan Channel is likely.

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SEASONAL VARIABILITY OF LIGHT ABSORPTION COEFFICIENT OF SURFACE WATER

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.28930/jitkt.v7i2.11121 ◽

2016 ◽

Vol 7 (2) ◽

Author(s):

Bisman Nababan ◽

Denny A. Wiguna ◽

Risti E. Arhatin

Keyword(s):

Gulf Of Mexico ◽

Absorption Coefficient ◽

Loop Current ◽

Surface Absorption ◽

Average Value ◽

Light Absorption Coefficient ◽

Run Off ◽

Significant Difference ◽

Northeastern Gulf Of Mexico ◽

Offshore Region

Absorption coefficient measurement can be used in estimating water quality, optical characteristic of water column, and marine bio-optical models. The purposes of this research were to determine values and variability of sea surface absorption coefficient in the northeastern Gulf of Mexico (NEGOM) based on various seasons. The data were collected in spring, summer, and fall seasons in 1999-2000 with AC-9 instrument. The spatial distribution of absorption coefficient showed that relatively high values were generally found along the run off Missisippi, Mobile, Chochawati, Escambia, Apalachicola, and Suwannee rivers, as well as Tampa Bay. Meanwhile, relatively low values were found in offshore region. This pattern followed the distribution pattern of chlorophyll and CDOM. Based on the local region comparison of spectral average value of absorption coefficient, we found a significant difference (α = 95%) among regions with the highest value in the run off of the Mississippi and Mobile rivers, and the lowest value in the offshore region. Comparison of spectral average value of absorption coefficient among seasons at the three primary wavelengths (blue=440 nm, green=510 nm, and red=676 nm) also showed a significant difference (α = 95%) with the highest value during the summer 1999 (Su-99) and the lowest value during the spring of 2000 (Sp-00). Absorption coefficient values were influenced by oceanographic factors that varied in every season such as wind, surface currents, upwelling, the location and speed of the Loop Current, and the river discharge of fresh water into the NEGOM.Keywords: absorption coefficient, seasons, chlorophyll, CDOM, northeastern Gulf of Mexico

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On the Mean Flow in the Western Gulf of Mexico and a Reappraisal of Errors in Ship-Drift Data

Journal of Physical Oceanography ◽

10.1175/jpo-d-19-0260.1 ◽

2020 ◽

Vol 50 (7) ◽

pp. 1983-1988

Author(s):

Wilton Sturges

Keyword(s):

Gulf Of Mexico ◽

Surface Flow ◽

Return Flow ◽

Loop Current ◽

Mean Flow ◽

The West ◽

Near Surface ◽

Southern Half ◽

The Mean ◽

Layer Flow

AbstractShip-drift data in the Gulf of Mexico have led to a perplexing result, that the near-surface flow in the west has a north–south mean, of the east–west flow, ~5–10 cm s−1 into a closed basin. Ship-drift data have been used in the past hundred years under the assumption that they are reasonably accurate; the present study examines that assumption carefully, finding that the standard deviation of individual observations is typically ~20 cm s−1. In a monthly mean composed of order 400 observations or more, as examined here, the standard error of the mean will be reduced accordingly. In the southern part of the western Gulf of Mexico, the observed upper-layer flow is clearly to the west and is consistent with our expectations. In the northern part, however, the apparent flow as reported by ship drift in deep water is not significantly different from zero. Thus, the puzzling result remains: three different datasets in the southern half of the basin clearly show flow to the west, with speeds of 10 cm s−1 or more, yet there is no clear evidence of a near-surface return flow back to the east. The convergent wind stress forces downwelling of the upper layer; its return flow could be at some intermediate depth. The transport to the west from Loop Current rings is possibly returned in a deep boundary flow driven by the rectification of deep topographic Rossby waves.

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Vertical Velocity and Vertical Heat Flux Observed within Loop Current Eddies in the Central Gulf of Mexico

Journal of Physical Oceanography ◽

10.1175/2008jpo3755.1 ◽

2008 ◽

Vol 38 (11) ◽

pp. 2461-2481 ◽

Cited By ~ 10

Author(s):

David Rivas ◽

Antoine Badan ◽

Julio Sheinbaum ◽

José Ochoa ◽

Julio Candela

Keyword(s):

Heat Flux ◽

Gulf Of Mexico ◽

Vertical Velocity ◽

Loop Current ◽

Coherent Signals ◽

Heat Temperature ◽

Vertical Heat ◽

Vertical Heat Flux ◽

Anticyclonic Eddies ◽

Acoustic Doppler Current Profilers

Abstract Sixteen months of observations from a surface-to-bottom mooring in the central Gulf of Mexico show that acoustic Doppler current profilers (ADCPs) are useful for directly measuring the vertical velocity within mesoscale anticyclonic eddies, such as those shed from the Loop Current; and combining simultaneous temperature measurements, vertical heat flux can also be estimated (as a covariance of both variables). There is evidence of significant and coherent signals of vertical velocity ∼2–3 mm s−1 and vertical heat (temperature) transport ∼10−3 °C m s−1 during the presence of three anticyclones. A simple analysis shows downward flow near the eddies’ centers above 350 m and essentially upward flow in the peripheries, but below 700-m depth the pattern is indeed the opposite; however, further study is necessary to determine the eddies’ interior structures. The observations also suggest the existence of a vertical convergence of heat somewhere around 600-m depth, and estimations of adiabatic heat flux suggest that part of the converged heat, which is not recirculated within the eddy, must escape from the eddy and flow upward along the isopycnals up to the surface layers. This is in good agreement with previous results that have suggested that an excess heat gained by the Gulf in the intermediate levels through exchanges with the Caribbean Sea must be exported to the upper layers by an upward mean heat flux.

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The Stratigraphy, Sedimentology and Chronostratigraphy of the Mobile Bay Fan, Northeastern Gulf of Mexico: ABSTRACT

AAPG Bulletin ◽

10.1306/a260083b-171b-11d7-8645000102c1865d ◽

1994 ◽

Vol 78 ◽

Author(s):

Donald B. Macurda, Jr., Gary Jones,

Keyword(s):

Gulf Of Mexico ◽

Mobile Bay ◽

Northeastern Gulf Of Mexico

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Distributional Differences and Population Similarities for Two Deep-Sea Crabs (Family Geryonidae) in the Northeastern Gulf of Mexico

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-236 ◽

1990 ◽

Vol 47 (11) ◽

pp. 2112-2122 ◽

Cited By ~ 7

Author(s):

F. D. Lockhart ◽

W. J. Lindberg ◽

N. J. Blake ◽

R. B. Erdman ◽

H. M. Perry ◽

...

Keyword(s):

Gulf Of Mexico ◽

Relative Abundance ◽

Deep Sea ◽

Seasonal Patterns ◽

Florida Current ◽

Loop Current ◽

Male And Female ◽

Northeastern Gulf Of Mexico ◽

Current Circulation ◽

Depth Zonation

For golden crab, Chaceon fenneri, and red crab, Chaceon quinquedens, numbers per trap, sex, and crab size were tested for broad bathymetric, geographic, and seasonal patterns on the upper continental slope, northeastern Gulf of Mexico. Red crab occupied only the deepest of three sampled depths (i.e. 677 m vs. 494 and 311 m) while golden crab predominated at the upper two. Golden crab occurred adjacent to peninsular Florida, but not along the northern Gulf slope, while red crab occurred across the geographic arc sampled. Relative abundance increased southward for golden crab and northwestward for red crab, while the proportion of females increased counter-clockwise within the sampled range of each species. Golden crab exhibited a Chaceon-typical bathymetric pattern of partial sex segregation and size inversely related to depth, but male and female bathymetric patterns shifted seasonally with lags between geographic areas. Interspecific competition cannot explain the species depth zonation, while geographic and seasonal patterns may relate to Loop Current–Florida Current circulation.

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